Hot functional tests begin at Finnish EPR

Finnish utility Teollisuuden Voima Oyj (TVO) announced today that hot functional tests have started at the first-of-a-kind EPR unit at Olkiluoto. These key pre-operational tests ensure coolant circuits and nuclear safety systems are functioning properly before fuel is loaded.

The Olkiluoto EPR, pictured in September 2016 (Image: TVO)

TVO said it expects the tests - which aim to simulate the temperatures and pressures which the reactor's systems will be subjected to during normal operation - to take several months.

"This is the first plant-level test where the nuclear island and the turbine island are operated together as a whole," TVO noted. "Several different tests at different pressure levels will be carried out during this stage. The water temperature is raised utilising the thermal energy produced by the reactor coolant pumps."

Cold functional tests - which are carried out to confirm whether components and systems important to safety are properly installed and ready to operate in a cold condition - began at Olkiluoto 3 (OL3) in June and took about four weeks to complete. The main purpose of these tests is to verify the leak-tightness of the primary circuit.

"After successful completion of the hot functional tests, it will be possible to obtain an operating licence for OL3 and continue the project towards nuclear commissioning," the company said.

The consortium of Areva GmbH, Areva NP SAS and Siemens AG began construction of Olkiluoto 3 in 2005 under a turnkey contract signed with TVO in late 2003. Completion of the 1600 MWe reactor was originally scheduled for 2009, but the project has suffered various delays and setbacks.

In October, the schedule for OL3 commencing regular electricity production was again revised from the end of 2018 to May 2019.

No counterfeit components

No parts have been used in the Olkiluoto EPR that "could endanger the safety of the plant due to uncertainties about their manufacturing history", the Finnish Radiation and Nuclear Safety Authority (Stuk) has concluded.

In May 2016, the French nuclear safety regulator said an ongoing quality audit at Areva's Le Creusot forge - which Areva bought in 2006 - had identified "irregularities" in paperwork on some 400 plant components produced there since 1965.

The following month, Stuk requested utilities Fortum and TVO investigate whether equipment whose material quality cannot be fully guaranteed had been supplied by the forge to their nuclear power units. TVO submitted its final report on the investigation into parts used in OL3 to Stuk on 16 November.

Stuk has now confirmed that the investigation into OL3 is complete and that TVO's inspections and investigations have "determined the quality of the materials used in the parts with sufficient certainty".

Investigations into components used in Finland's operating plants - Loviisa units 1 and 2 and Olkiluoto 1 and 2 - have also found that no parts with inadequate or counterfeited documentation have been supplied by Areva.